a jQuery function to get either all the transition times or just the longest css transition time on an element.

getTransitionSpeed.js

function getTransitionSpeed( $el , returnWholeArray ) {
    
    returnWholeArray = returnWholeArray || false;
    
    var speed = $el.css("transition-duration").split(","),
        speedLength = speed.length;
    
    for( var i = 0; i < speedLength; i++) {
    
        var multiplier = 1000;
    
        speed[i] =
            speed[i]
                .replace(" ","")
                .replace("s","");
    
        speed[i] = parseFloat( speed[i] ) * multiplier;
    
    }
    
    if( returnWholeArray ) {
        return speed;
    } else {
        return Math.max.apply(Math, speed);
    }
    
}